/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.http.server.reactive.bootstrap;

import java.util.LinkedHashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.http.server.reactive.ContextPathCompositeHandler;
import org.springframework.http.server.reactive.HttpHandler;
import org.springframework.util.Assert;
import org.springframework.util.StopWatch;

/**
 * @author Rossen Stoyanchev
 */
public abstract class AbstractHttpServer implements HttpServer {

    protected Log logger = LogFactory.getLog(getClass().getName());

    private String host = "0.0.0.0";

    private int port = 0;

    private HttpHandler httpHandler;

    private Map<String, HttpHandler> handlerMap;

    private volatile boolean running;

    private final Object lifecycleMonitor = new Object();


    @Override
    public void setHost(String host) {
        this.host = host;
    }

    public String getHost() {
        return host;
    }

    @Override
    public void setPort(int port) {
        this.port = port;
    }

    @Override
    public int getPort() {
        return this.port;
    }

    @Override
    public void setHandler(HttpHandler handler) {
        this.httpHandler = handler;
    }

    public HttpHandler getHttpHandler() {
        return this.httpHandler;
    }

    public void registerHttpHandler(String contextPath, HttpHandler handler) {
        if (this.handlerMap == null) {
            this.handlerMap = new LinkedHashMap<>();
        }
        this.handlerMap.put(contextPath, handler);
    }

    public Map<String, HttpHandler> getHttpHandlerMap() {
        return this.handlerMap;
    }

    protected HttpHandler resolveHttpHandler() {
        return (getHttpHandlerMap() != null ?
                new ContextPathCompositeHandler(getHttpHandlerMap()) : getHttpHandler());
    }


    // InitializingBean

    @Override
    public final void afterPropertiesSet() throws Exception {
        Assert.notNull(this.host, "Host must not be null");
        Assert.isTrue(this.port >= 0, "Port must not be a negative number");
        Assert.isTrue(this.httpHandler != null || this.handlerMap != null, "No HttpHandler configured");
        Assert.state(!this.running, "Cannot reconfigure while running");

        synchronized (this.lifecycleMonitor) {
            initServer();
        }
    }

    protected abstract void initServer() throws Exception;


    // Lifecycle

    @Override
    public final void start() {
        synchronized (this.lifecycleMonitor) {
            if (!isRunning()) {
                String serverName = getClass().getSimpleName();
                if (logger.isDebugEnabled()) {
                    logger.debug("Starting " + serverName + "...");
                }
                this.running = true;
                try {
                    StopWatch stopWatch = new StopWatch();
                    stopWatch.start();
                    startInternal();
                    long millis = stopWatch.getTotalTimeMillis();
                    if (logger.isDebugEnabled()) {
                        logger.debug("Server started on port " + getPort() + "(" + millis + " millis).");
                    }
                } catch (Throwable ex) {
                    throw new IllegalStateException(ex);
                }
            }
        }

    }

    protected abstract void startInternal() throws Exception;

    @Override
    public final void stop() {
        synchronized (this.lifecycleMonitor) {
            if (isRunning()) {
                String serverName = getClass().getSimpleName();
                logger.debug("Stopping " + serverName + "...");
                this.running = false;
                try {
                    StopWatch stopWatch = new StopWatch();
                    stopWatch.start();
                    stopInternal();
                    logger.debug("Server stopped (" + stopWatch.getTotalTimeMillis() + " millis).");
                } catch (Throwable ex) {
                    throw new IllegalStateException(ex);
                } finally {
                    reset();
                }
            }
        }
    }

    protected abstract void stopInternal() throws Exception;

    @Override
    public boolean isRunning() {
        return this.running;
    }


    private void reset() {
        this.host = "0.0.0.0";
        this.port = 0;
        this.httpHandler = null;
        this.handlerMap = null;
        resetInternal();
    }

    protected abstract void resetInternal();

}
